Sorry for those of you who read this post on the other forum. I'm just getting to know my way around and finding where the fellow civic owners hang out...

I've had a strange problem pop up once in a while on my '04 Civic Hybrid (CVT), but never when a technition is driving it (of course!).

I never feel the shifting, which is correct, except for once in a while when I have been driving steady speeds after the car warms up. Then when I slow down and speed up again (say, for a stop light or an interchange), I feel a hard shift, kind of a slamming into gear. I've been observing, and it really only happens when it's foggy or there's high humidity.

Does anyone have any input on whether this is normal or a problem? Does this happen to anyone else? What should I tell the service guys to look for? What in the world could be wrong?

Thanks!
--Adelwyn

 

You know, I just noticed it yesterday. Its hard to reproduce on demand, but it happened quite a bit in traffic yesterday on my 06 HCH. For me, when I get down to about 10 mph, then re-accelerate, I feel the engine diengage and fire the ICE back up fine, but now, I feel a SECOND kick, and its not a polite one. It didn't use to do that before. Its only at this lower speed, so I don't really want to have to take it in. The fact that I can't purposely reproduce it makes it not such a big deal to me. But it could get worse, And that, I'm scared of. I will experiement with it today and see what happens.

 

Hi Amy & Luis;

This was my suggestion to Amy in Her other Post but it Applies to both of your Situations. Good-Luck !!!!!

Hi Amy;

I'll get right to the Point on this.

There is only (IMO) In-My-Opinion one way this is going to get Corrected.

Amy, Your car is going to {Have-To} be doing this Strange Shifting thing so that you can get,
the (Service-Manager) or (Service-Director) to go for a Ride (With-You) so you can show
Them what is going on.

If you cannot get the car to show these every once in awhile Shifting-Smyptoms you will not get this Problem Resolved. The Techs. in most cases do not have the time to drive a persons vehicle long enough to show something like this up. They will drive it and if it is Performing as they know it should, there is nothing they can do at that point to Fix/Repair something that is not showing anything is Wrong.

Amy; if you will do as I have outlined in {Green} above you will get your vehicle repaired.

Good-Luck:

Terry

BTW; Amy I have worked at a Dealership for the past 10-Years.

 

When a CVT starts jerking and complaining,, change the fluid in them. They are fringe trannys. They have been around for years but have never gotten anywhere cause they break alot.

Kinda like wankle engines. Great high output screaming engines and easy to get great hp out of. But the crank does 3 rpms for every rpm the rotor does. So if the tachs saying a rpm of 6k rpm the crank is at 18k rpm. Somethings going to give. Maybe less moving parts in a wankle engine than a 4 cylinder engine. but those fewer parts are takeing a much worse beating.

Same with a CVT. Sure the advent of computers have made them much better for control but you still have fewer parts taking a worse beating. In the most basic fourm of a CVT you will have two pulleys and one belt. One pulley is static. This would be the final drive pulley. The other is a varible pully. It opens and closes to very ratios. You drive alot on the frewway at 57 to 62 mph. The varible pully is going to wear a groove in the running surfaces in that area. It may only be a .001 to .010 groove but none the less the belt will try and track to it. You speed up the pully slowly closes to get you in the right place for the torque required and the lower ratio to move the car. The belt wants to hang in the groove. But then is forced out by the closure of the pully... Theres a pop. As you reach speed and the pully starts opening it gets back near it wear area then drops in... Theres a pop. So now we are at 62 mph and wow we are in our target wear area again. The belts happy and alls fine... Nope.... we want to go a bit faster to make a creeping pass so we let our speed drift up to 67 mph. The pully opens more for a higher ratio but the belt has to go down now past it common wear point. But there the bottom edge of the wear area the belt has to deal with. Belt see's that lower wear area and pops on that lower transition spot. Yet another pop felt by the drive and another shock wave that goes right thru the bearing and the acuator system.

There just not ready for prime time. If they where they would have replaced hydraulic gear and clutch trannys years ago.

The best thing you can do for a CVT is to very your driveing loads and speeds to wear the pullys even through out there running surfaces and for gods sake ,,, change the CVT fluid at a min. of every 3rd oil change.

CVT's are bad for long term use and useing one to get the most out of it makes it a bad FE choice in trannys. all there good for is to max a producers bottomline and max out margin. Fewer parts easy construction means more $$$ for them. and then they can sell it at a premium... Equals more $$$ for them. They really dont care about the end user. if they did they would have offered a 5 or 6 speed MT or standard AT.

Toyotas CVT if I remember right has two varible pullys which will spread the load over more of the surface area of the pullys. There both always moving looking for that perfect load curve and the tranny has less horsepower and torgue to deal with over all. So it may well last longer.

Shame on Honda for putting there intrest over excited owners of HCH's with whimpy whiz bang 2nd order tech.

 

ooh, a six speed MT, now that is what I want,
I could pretend I am driving a vette. :-)

Actually I think you are the first person to explain to me how a CVT works
in a way I could understand. At least I can visualize something sensible
from what you said. I also visualize a cone shaped something, for the belt
to move back and forth over under control of the moving pully, that is
the thing that develops the grooves right?

Belts and pullys reminds me of the chain drive in the original Honda CVCC.
It worked, but people laughed when they heard about it.

- kmh3

 

Try this link.

http://auto.howstuffworks.com/cvt.htm

Good luck

 

Thanks for the input....
The theory about groove in the transmission certainly sounds logical to me. If this is the case, I guess there's not much I can do about it--except make sure to have my fluids changed frequently and to vary my speeds... right? Is it going to get worse over time?

I'm still wondering, however-- it doesn't do it often (or at least, I don't feel it often), and only once the first time I slow down/speed up after it warms up. Then it usually won't do it again in the same trip (which is why I've had a hard time showing the techs the problem).

And is it just coincidence that it seems to only happens when it's foggy/high humidity?

Or do these conditions make the groove in the runny surfaces of the tranny more noticable?

--Amy

 

The post was not ment to say what your problem is. Just a overview of a problem Ive seen in simple CVT applications over the years. Read the link posted above and it will give you insite into the popular configs of CVT's used today.

 

I read the how CVT's work article, the pictures were outstanding.

thanks,
- Kurt

 

I get that in my CTV occasionally too. It seemed to happen at least once per trip for a couple weeks, then it all but disappeared. I sometimes think it's a delay in the car re-engaging the tranny after coasting, decelerating or stopping. Like it's running free for a half second before engaging, maybe a little like dumping the clutch or revving in neutral and dumping it into D. Something like that. It hasn't happened for a while though and I can't think of anything that changed to blame it on.

psyshack, I think you have a good point about wearing a groove. However, I differ in a couple points. First of all, in the cvt both pulleys have to be variable. If one were fixed and the other variable, then the length of the belt would have to change to change the ratio, and I am pretty sure that's not happening.
Second, small cars have been using CVTs for years in europe. While it is new to the states, they're not a new idea for cars and that's one reason I wasn't afraid to get one. There may be some growing pains as the technology develops for larger vehicles, but that will only come with using them, so I'm all for it.